Objective: To investigate the correlation between the occurrence of anterior communicating artery aneurysm and the variation type of anterior cerebral artery. Methods: Three-dimensional computed tomography angiography (CTA) techniques were used to reveal the morphological structure of the brain’s circle of Willis and to record the types of anterior cerebral artery variants. The imaging data of 106 patients with anterior communicating artery aneurysm diagnosed by CTA in head and neck were retrospectively analyzed. According to the type of Willis ring anterior circulation variation, the 106 patients were divided into cerebral anterior artery A1 segment absent group, A1 segment dysplasia, slender group and A1 segment. In the balanced group, 120 healthy controls were selected and statistical analysis was used to compare the differences in the A1 segment variation of the anterior cerebral artery. Results: There was a statistically significant difference between the anterior cerebral artery A1 segment deficiency group, the A1 segment dysplasia group, and the A1 segment equilibrium group (χ2=38.349, P<0.001). Conclusion: There was a significant correlation between the variability of the anterior cerebral artery A1 segment and the incidence of anterior communicating artery aneurysms. CTA can accurately display the type of variation of the Willis ring in the brain and the location of the aneurysm, especially the lack of the A1 segment, which has great guiding value for clinical diagnosis and treatment.